Method and apparatus for sizing tubes



Oct. 17, 1939. w. .1. ASSEL METHOD AND APPARATUS FOR SIZING TUBES FiledAug. 19, 1936 2 Sheets-Sheet 1 Oct. 17, 1939. w. J. ASSEL METHOD ANDAPPARATUS FOR SIZING TUBES Filed Aug. 19, 1936 2 Sheets-Sheet 2 PatentedOct. 17, 1939 UNITED STATES PATENT OFFICE Walter J. Ansel, Canton, Ohio,assignor to The Timken Roller Bearing Company,

Canton,

Ohio, a corporation of Ohio Application August 19, 1936, Serial No.96,745

18 Claims.

The final operation in seamless tube rolling mills is to size the tubeto the final size desired. According to common practice, this sizing isdone by passing the tube through two-high grooved roll stands arrangedcontinuously in line with the axes of the rolls of each stand set at anangle of ninety degrees with the adjacent stands. In the case of tubingof a diameter of three inches or larger this sizing is done in a millconsisting m of three to flve stands only. If the finished tubing is tobe less than three inches it is reduced in size by passing through fromthree to twelve oval grooved roll stands which sink or reduce thediameter. The last three stands of mach a 1n mill act as sizing stands,forming the tube to a round shape and bringing it to size. Such groovedroll mills are subject to a number of disadvantages. They requiredifferent sets of rolls for every size of tube; the rolls wear rapidlyand, when worn, require to be replaced or redressed; the replacement andadjustment of the rolls requires considerable skill and time duringwhich the entire mill is out of commission; and frequently the productbears marks on 5 its surface produced by the parting of the rolls andmisalignment and is not as accurate as desirable either in diameter orroundness.

The principal object of the present invention is to devise a method anda mill which will do! 9 the work of the sinking and sizing mill butwhich will be free from the disadvantages above mentioned. It is aprincipal object of the invention to devise a mill that will do the workof sinking and sizing in a single pass; another object is to devise amill whose pass-forming rolls are adjustable for tubes of differentsizes. Another object is to devise a mill that will sink and size tubingmore accurately as to diameter and roundness than has heretofore beenfeasible with w sinking and sizing mills; another object is to simplifyand facilitate the operation of adapting the mill for tubes of differentsizes. The invention consists in the method and in the apparatus andwork roll hereinafter described and claimed.

4,5 It also consists in the parts, combinations and arrangements ofparts hereinafter described and claimed.

In the accompanying drawings, which form part of this specification andwherein like sym- 60 hole refer to like parts wherever they occur.

Fig. 1 is a diagrammatic view showing the grouping of the work rolls ofmy mill;

Fig. 2 is a longitudinal sectional view along the line of contact of oneroll with the tube being ll sized;

Fig. 3 is an enlarged fragmentary view similar to Fig. 2; and

Figs. 4 to 8 illustrate modified forms of roll and roll arrangements.

The present mill comprises suitable framework and housing for work rollstogether with suitable mechanism for adjusting and driving the same.Reference is hereby made to my copending application Serial No. 727,934filed May 28, 1934 for a full description of framework, housing andadjusting and driving mechanism suitable for use in my present mill.

The present mill comprises a series of work rolls l, preferably three orfour, arranged with their axes in planes parallel with and equidistantfrom the axis of the mill and from each other and inclined respectivelyat an angle in the neighborhood of from five to ten degrees to a planepassing through the axis of the mill and intersecting the respectiveroll axis near the middle thereof. The angle thus defined is commonlycalled the feed angle of the rolls. This feed angle determines the pitchor distance which the tube moves longitudinally during a single rotationthereof; and this distance divided by the number of equidistant rollsconstituting the pass is commonly called the advance" of the tube. Therolls are similarly arranged with respect to the axis of the mill, thatis, each roll is so disposed that if it were revolved about the axis ofthe mill to the location of another roll, it would take the sameposition and arrangement as such other roll.

Each work roll comprises a. cylindrical zone A which is located at ornear the middle portion of the roll and is of the maximum diameter ofthe roll. Along one side (hereinafter referred to as the forward side)of the cylindrical zone is a relatively narrow longitudinally convexzone B whose surface is preferably tangent to or merges into the surfaceof the cylindrical zone. Alongside of the convex zone is a relativelywide conical zone C which makes an obtuse angle with said zone B andtapers slowly toward the end of the roll and emerges into a narrowendmost zone D that is convex or rounded. In practice, I have hadsatisfactory results when the side of this conical zone C inclined atthe rate of one unit in twelve at an angle of about two and one-halfdegrees to the axis thereof, which is equivalent to an apical angle ofabout five degrees. Along the other or back side of said cylindricalzone A is a second conical zone E that tapers more slowly than zone Cclose to the other end of the roll where it merges into a narrow,rounded or convex zone F. In practice. I have had satisfactory resultswhen the apical angle of this conical zone E was about two and one halfdegrees, which is equivalent to inclining the side of said zone aboutone unit in fortyeight with relation to the axis thereof.

By reason of the oblique angle between the zones B and C, the zone Bconstitutes an inclined shoulder; and this shoulder is an importantelement in effecting the sizing action as it is located at the gorge ofthe pass. On account of the nature of the work, this shoulder is quitelow. For instance, for sizing small tubing of from one and one-halfinches to three inches in outside diameter with rolls of about ten oreleven inches in diameter, I have had very satisfactory results when thedifference between the least diameter of the shoulder of zone B and thediameter of the cylindrical zone A is of the order of one-twentieth ofan inch, with a longitudinal width of from about three-eighths toliveeighths of an inch. The width of this low shoulder or convex zone isseveral times its height, say, about ten to twelve times; and as it isthe gorge-forming part of the roll, its width and low angle causeconsiderable frictional resistance to the plastic flow of the metal in alongitudinal direction.

The work rolls are positioned with their shoulders facing the enteringside of the mill and with the proximate surfaces of the conical zones Ein planes substantially parallel with the axis of the mill. In thisposition, the proximate surfaces of the zones C converge slightly to theshoulders that form the gorge of the pass; and the work rolls are soadjusted that the circle of the gorge or narrowest portion of the passwill lie in a plane which passes through or close to the large ends ofthe portions of the roll shoulders in contact with the tube and will beof the diameter required to produce the desired flnished tube.

In the practical operation of the mill hereinbefore described, nomandrel or wall support is used inside of the tube. The tube T to besized is entered between the rolls endwise at a temperature suitable forrolling, preferably about 1400 to l600 Fahrenheit for steel tubing, andis reduced slightly to the desired outside diameter, which is determinedby the adjustment of the pass. The tendency of the tube is to seatitself on the lowermost rolls and the first function of the rolls is toaccurately center the tube with respect to all of the rolls. Thisfunction is accomplished by sliding the tube endwise along theconverging surfaces of the forward portions of the zones C of the lowerrolls until the tube comes in contact with the upper roll or rolls. Thesecond function of the rolls is to simultaneously rotate the tube andfeed it longitudinally, which i'uncion is accomplished by the rearwardportions of zones C which portions are continuations of the centeringsurfaces of said zones C. The third function of the rolls is to slightlyreduce the outside diameter of the tube, which function is performedmainly by the shoulders or zones B, at the rear edges of which the rollsreach their maximum diameter. The principal function of the cylindricalzone A is to nullify the tendency of the shoulders to form helical markson the tube as well as to feed. This tendency is minimized by the lowinclination of the shoulders and is practically overcome by thecylindrical zones A into which the shoulders merge at their greatestdiameter and in the plane of the gorge, beyond which the pass 'verygradually increases in diameter throughout the width of the cylindricalzones A, by reason of the skewing of the rolls. Accordingly, the widthof the cylindrical zone A is slightly more than the advance of the tubein its helical movement from one roll of the pass to the next roll. Thiscylindrical zone A also functions to reel the tube and aids incontrolling the feed thereof and the plastic flow of the metal. Zone Eserves to round up ti: tube which is slightly distorted at zone A, andguides the tube toward the outlet of the mill.

In practical operation, zone C of the rolls will get a frictional gripon tubes requiring a greater reduction to size at a more forwardposition than is the case with tubes requiring less reduction, due tothe taper on zone C. This is an advantage because tubes requiring thegreater reduction require greater feed pressures inasmuch as more metalmust be displaced on such tubes.

In practical operation, there is nothing inside the tube to resistradial flow of the metal, and the metal displaced in the operation ofreducing the outside diameter of the tube goes mainly to increase thewall thickness of the tube with only a slight elongation of the tube.One of the factors contributing to this result is the great frictionalresistance to the longitudinal flow of the metal due largely to the longlines of contact with the work rolls and particularly to thelongitudinal flow angle being very low, such longitudinal flow anglebeing the angle between the lines in which a plane through the axis ofthe pass intersects the surface of the roll shoulder and the adjacentinner surface of the tube.

It is an important advantage of my invention that the tubes sizedthereby are more truly circular and closer to size and freer fromlongitudinal surface marks than the product of the ordinary sinking andsizing mill, Besides, my operation requires much less apparatus. It is aspecial advantage of my apparatus that it is adjustable and that thesame rolls can be used for tubes of different sizes and are notseriously affected by wear that would be ruinous to the rolls of thecommon sinking and sizing mill. Heretofore, the reduction of thediameter of tubing has usually been accompanied with varying elongationand an unequal heavying-up of the wall thickness, resulting inout-of-round holes in the tubing. It is a considerable merit of myinvention that it enables the diameter of the tubing to be decreased andthe wall thickness to be uniformly increased. While I have described myprocess as applied to the sizing of hot steel tubing, it is applicablealso to tubing of other metals, such for instance, as copper or brasstubing which requires little or no heating.

Fig. 4 shows a modified design of roll positioned with reference to thepass line and with the arrow indicating the direction of movement of thework. This roll is of general conical shape with an enclosed apicalangle of about 20, that is, the element of the imaginary cone makes anangle of about 10 with the axis thereof. About midway of the roll is alongitudinally convex zone, alongside of which on the front or enteringside is a conical surface radially beyond the general imaginary cone andmeeting said imaginary cone at the front end of the roll, making anangle of about 5 therewith. Alongside of said convex zone on the rearside thereof is a conical zone that makes an angle of about 2% with theimaginary general cone. The convex zone merges into the rear conicalzone and makes a very 7 wide angle with the forward conical zone andthus forms a very low rib.

In the modification illustrated in Pig. 5, the roll is of maximumdiameter about midway between its ends where there is a convex zone oflarge radius and from this convex zone the surface of the roll tapers inboth directions, the taper on the forward or entering side being abouttwo inches per foot on the diameter and the taper on the rear side beingabout one inch per foot on the diameter; that is, the forward zoneinclines toward the axis of the roll at an angle of about 5; and thesurface of the rear conical zone tapers toward the axis at an angle ofabout 2%. The working position of the roll with reference to the passline is shown in Fig. 5 and the direction of movement is indicated bythe arrow therein.

My process of sizing is not dependent on the specific type of tube millhereinbefore described but may be carried out with mills of other typesknown in the art. Thus, all of the roll axes may lie in planes parallelwith the pass; or one roll axis may diverge from the pass in thedirection of feed and the coacting roll axis, or axes, converge towardthe pass in the direction of feed; or all roll axes may diverge from thepass in the direction of feed. The important consideration is that thepass shall converge in the direction of feed so slowly that thefrictional resistance to longitudinal flow of the metal is greater thanthe resistance to flow thereof in a radial direction when there is nointerior support for the metal.

Figs. 6 and 7 illustrate diagrammatically a tube mill of the Stiefel ordisk-roll type adapted and arranged for carrying out my process, thecoacting disk rolls overlapping in Fig. 6 and being opposite each otherin Fig. 7. In both cases, however, the pass forming portions of the diskrolls converge in the direction of feed at such a low angle that thefrictional resistance to longitudinal flow of the metal is greater thanthe resistance of the unsupported wall of the tube to fiow of the metalradially inwardly. As indicated in Figs. 6 and '7, I prefer to have thepass-forming surfaces incline at an angle in the neighborhood of fivedegrees to the pass line and to have the reeling surfaces diverge fromthe pass line at an angle in the neighborhood of two and one-halfdegrees; but these angles admit of variation.

It is not necessary that all of the rolls should be of the same kind.For instance, as illustrated in Fig. 8, one of the rolls may be of thedisk type and its mate may be of barrel or conical shape; but in allcases, the longitudinal flow angle should be small enough to bring abouta frictional resistance to longitudinal flow that is greater than theresistance to radial flow of the unsupported wall.

The process of sizing hereinbefore described is especially applicable tothe production of tubing within close limits of tolerance and is notdependent upon any particular method or apparatus for converting thework piece into the tube to be sized. In practice, the hot work piece isconverted by any suitable mill into a rough or unfinished tube whosediameter approximates but is somewhat larger than the diameter of thefinished tube. Then, while the tube is still hot, it is cross-rolledwithout interior support between rolls or pass-forming members soarranged that the frictional resistance to the longitudinal flow of themetal is greater than the resistance therepracticable to size withoutchanging the setting;

and, of course, it is a greater advantage that the same rolls may be setto produce finished tubes of diflei'ent diameters.

What I claim is:

1. A tube sizing mill comprising a series of rolls similarly arrangedequidistantly from the axis of the pass with their own axes askew withrelation to the planes of said axis to form a slowly converging pass,each roll being of greatest diameter near the middle thereof anddecreasing slowly toward both ends thereof, the rate of decrease beingmost rapid in a narrow gorge-forming zone next forward of the zone ofmaximuni diameter whereby a low inclined shoulder is formed thereonwhose width is several times its height and whose surface merges intothe zone of greatest diameter.

2. A tube sizing mill comprising a series of rolls similarly arrangedequidistantly from the axis of the pass with their own axes askew withrelation to the planes of said axis, each work roll comprising acylindrical zone of the maximum diameter of the roll and located at themiddle portion of the roll, a longitudinally convex zone alongside ofthe forward edge of said cylindrical zone and with its surface merginginto the surface of said cylindrical zone, a conical zone alongside ofsaid convex zone and tapering slowly toward one end of the roll, and asecond conical zone alongside of said cylindrical zone and tapering moreslowly toward the other end of the roll.

3. A tube sizing mill comprising a series of pass-forming rollssimilarly arranged equidistantly from the axis of the pass with theirown axes askew with relation to the planes of said axis, each roll beingof greatest diameter near the middle thereof and decreasing to both endsthereof, the rate of decrease being most rapid in a narrow zone nextforward of the zone of maximum diameter whereby a low inclined shoulderis formed thereon whose surface merges at the gorge of the pass into thezone of'greatest diameter and whose width is somewhat greater than theadvance of the work piece.

4. A tube sizing mill comprising a series of pass-forming rollssimilarly arranged equidistantly from the axis of the pass with theirown axes askew with relation to the planes of said axis, each roll beingof geratest diameter near the middle thereof and decreasing to both endsthereof, the rate of decrease being most rapid in a narrow zone nextforward of the zone of maximum diameter and of a width of several timesits height whereby a low inclined shoulder is formed thereon whosesurface merges at the gorge of the pass into the zone of greatestdiameter and whose width is somewhat greater than the advance of thework piece.

5. A tube sizing mill comprising a series of pass-forming rollssimilarly arranged equidistantly from the axis of the pass with theirown axes askew with relation to the planes of said axis, each work rollcomprising a cylindrical zone of the maximum diameter of the roll whosei'll proximate elements are nearly parallel with the axis of the passlocated at the middle portion of the roll and of a width somewhatgreater than the longitudinal advance of the work between successiverolls, a longitudinally convex zone alongside of and merging with theforward edge of said cylindrical zone and of a width of about ten timesits height and located atthe gorge of tire pass, a conical zonealongside of said convex zone and tapering toward one end of the rollwith an apical angle of about five degrees, and a second conical zonealongside of said cylindrical zone and tapering toward the other end ofthe roll with an apical angle of about two and onehalf degrees.

6. A tube sizing mill comprising a series of pass-forming rollssimilarly arranged equidistantly from the axis of the pass with theirown axes askew with relation to the planes of said axis. each work rollcomprising a cylindrical zone 01' the maximum diameter of the rolllocated at the middle portion of the roll and of a width somewhatgreater than the longitudinal advance of the work between successiverolls, a longitudinally convex zone alongside of and merging with theforward edge of said cylindrical zone and located at the gorge of thepass, the width of said convex zone being several times its height, aconical zone alongside of said convex zone and tapering toward one endof the roll with an apical angle of about five degrees, and a secondconical zone alongside of said cylindrical zone and tapering toward theother end of the roll with an apical angle of about two and one halfdegrees.

7. A work roll for a tube sizing mill oi the kind described comprising anarrow cylindrical zone of the maximum diameter of the roll and locatedat the middle portion 01' the roll, a narrow longitudinally convex zonealongside of and merging tangentially with said cylindrical zone, andforming a shoulder whose width is about ten to twelve times its height,a relatively wide conical zone alongside of said convex zone andtapering slowly toward one end of the roll, and a second conical zonealongside of said cylindrical zone and tapering more slowly toward theother end of the roll.

8. A work roll for a tube sizing mill oi the kind described comprising anarrow cylindrical zone of the maximum diameter of the roll and locatedat the middle portion of the roll, a narrow longitudinally convex zonealongside of and merging tangentially with said cylindrical zone, aconical zone alongside of said convex zone and tapering slowly towardone end of the roll, and a second conical zone alongside of saidcylindrical zone and tapering more slowly toward the other end of theroll.

9. A work roll for a tube sizing mill of the kind described comprising anarrow cylindrical zone of the maximum diameter of the roll and locatedat the middle portion of the roll, a narrow longitudinally convex zonenext to each side of said cylindrical zone and merging tangentiallytherewith, a conical zone alongside of said convex zone and taperingslowly toward one end of the roll. and a second conical zone alongsideof the other convex zone and tapering more slowly toward the other endof the roll.

10. A work roll for a tube sizing mill of the kind described comprisinga cylindrical zone of the maximum diameter of the roll and located atthe middle portion of the roll, a second narrow zone alongside of andcontinuous with said cylindrical zone and gradually decreasing indiameter away from said cylindrical zone and constituting a low shoulderwhose smallest diameter is about one twentieth of an inch less than itslargest diameter. a conical zone alongside of said second zone andtapering slowly toward one end of the roll, and a second conical zonealongside of said cylindrical zone and tapering more slowly toward theother end of the roll.

ii. A work roll for a tube sizing mill of the kind described comprisingacylindrical zone of the maximum diameter of the roll and located at themiddle portion of the roll, a second zone immediately alongside of andcontinuous with said cylindrical zone and of even diameter therewithwhen they meet and gradually decreasing in diameter away from saidcylindrical zone and constituting a low shoulder whose width is severaltimes its height, a conical zone alongside of said second zone andtapering slowly toward one end of the roll, and a second conical zonealongside of said cylindrical zone and tapering more slowly toward theother end of the roll, said second zone being slightly wider than the advance of the work piece.

12. A work roll for a tube sizing mill or the kind described comprisinga cylindrical zone of the maximum diameter of the roll and located atthe middle portion of the roll, a relatively narrow longitudinallyconvex zone alongside of and merging tangentially into said cylindricalzone, a conical zone alongside of and making an oblique angle with saidconvex zone and tapering slowly toward one end of the roll, and a secondconical zone alongside of and merging with said cylindrical zone andtapering more slowly toward the other end of the roll.

13. A work roll for a tube sizing mill or the kind described comprisinga cylindrical zone of the maximum diameter of the roll and located atthe middle portion of the roll, a relatively narrow low longitudinallyconvex zone alongside of and merging into said cylindrical zone and of awidth of about ten to twelve times its height, the diameter of the smallend of said convex zone being about one-twentieth of an inch less thanthe diameter of the large end thereof, a conical zone alongside of andmaking an oblique angle with said convex zone and with its sidestapering at the rate of about one in twelve toward one end of the roll,and a second conical zone alongside oi and merging with said cylindricalzone and with its sides tapering at the rate of about one in twenty-fourtoward the other end 01' the roll.

14. A work roll for a tube sizing mill of the kind described comprisinga cylindrical zone of the maximum diameter 0! the roll and located atthe middle portion of the roll, a longitudinally convex zone next toeach side of said cylindrical zone and of equal diameter therewith wherethey meet, a conical zone alongside of the forward convex zone andtapering slowly toward one end of the roll, and a second conical zonealongside of the other convex zone and tapering more slowly toward theother end of the roll, the forward convex zone being narrow relativelyto the forward conical zone but somewhat wider than the advance of thework piece.

15. A work roll for a tube sizing mill 0! the kind described comprisinga narrow cylindrical zone of the maximum diameter of the roll andlocated at the middle portion of the roll, a narrow longitudinallyconvex zone next to each side of said cylindrical zone and mergingtangentially therewith, a conical zone alongside oi the forward convexzone and tapering with an apical angle 1 of about ten degrees toward oneend of the roll, and a second conical zone alongside of the other convexzone and tapering with an apical angle of about five degrees toward theother end of the roll.

16. The method of sizing tubing which comprises cross-rolling hottubing, without interior support, between three or more skewed rolls inthree immediately consecutive pass stages in the first of which the workpiece is rotated and fed forwardly without appreciable convergence ofits wall, in the second of which the wall of the work piece is convergedonly slightly, and in the third of which the work piece is reeledwithout further convergence of its wall, the middle pass stage beingnarrow relatively to the other stages but somewhat wider than theadvance of the work piece and merging into the third stage parallel withthe axis of the work piece.

17. The method of sizing tubing which comprises cross-rolling hottubing, without interior support, between three or more skewed rolls inthree immediately consecutive pass stages, in the first of which thework piece is rotated and fed forwardly with a frictional grip withoutappreciable convergence of its well, in the second of which the wall ofthe work piece is converged only slightly, and in the third 01' whichthe work piece is reeled without further convergence of its wall, themiddle pass stage being narrow relatively to the other pass stages andmerging into the third stage without any angle' between them.

18. The method of sizing tubing which comprises cross-rolling hottubing, without interior support, between three or more skewed rolls inthree immediately consecutive pass stages, in the first of which thework piece is rotated and fed forwardly with a frictional grip withoutappreciable convergence of its wall, in the second of which the wall ofthe work piece is converged only slightly altogether and at a decreasingrate, and in the third of which the work piece is reeled without furtherconvergence of its wall, the middle pass stage being narrow relativelyto the other pass stages and merging into the third stage without anyangle between them.

W. J. ASSEL.

CERTIFICATE OF CORRECTION Patent No. 2,176,1 12.

October 17, 1959.

WALTER J. ASSEL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1;,first column, line t l cleim'f, before "second" insert relatively wide;and that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Office.

Signed and sealed this 12th day of December, A. D. 1959.

(Seal) Henry Van Arsdale, Acting Commissioner of Patents.

of about ten degrees toward one end of the roll, and a second conicalzone alongside of the other convex zone and tapering with an apicalangle of about five degrees toward the other end of the roll.

16. The method of sizing tubing which comprises cross-rolling hottubing, without interior support, between three or more skewed rolls inthree immediately consecutive pass stages in the first of which the workpiece is rotated and fed forwardly without appreciable convergence ofits wall, in the second of which the wall of the work piece is convergedonly slightly, and in the third of which the work piece is reeledwithout further convergence of its wall, the middle pass stage beingnarrow relatively to the other stages but somewhat wider than theadvance of the work piece and merging into the third stage parallel withthe axis of the work piece.

17. The method of sizing tubing which comprises cross-rolling hottubing, without interior support, between three or more skewed rolls inthree immediately consecutive pass stages, in the first of which thework piece is rotated and fed forwardly with a frictional grip withoutappreciable convergence of its well, in the second of which the wall ofthe work piece is converged only slightly, and in the third 01' whichthe work piece is reeled without further convergence of its wall, themiddle pass stage being narrow relatively to the other pass stages andmerging into the third stage without any angle' between them.

18. The method of sizing tubing which comprises cross-rolling hottubing, without interior support, between three or more skewed rolls inthree immediately consecutive pass stages, in the first of which thework piece is rotated and fed forwardly with a frictional grip withoutappreciable convergence of its wall, in the second of which the wall ofthe work piece is converged only slightly altogether and at a decreasingrate, and in the third of which the work piece is reeled without furtherconvergence of its wall, the middle pass stage being narrow relativelyto the other pass stages and merging into the third stage without anyangle between them.

W. J. ASSEL.

CERTIFICATE OF CORRECTION Patent No. 2,176,1 12.

October 17, 1959.

WALTER J. ASSEL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1;,first column, line t l cleim'f, before "second" insert relatively wide;and that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Office.

Signed and sealed this 12th day of December, A. D. 1959.

(Seal) Henry Van Arsdale, Acting Commissioner of Patents.

